how detailed do you want?
I assume you know that path refers to a list of directories where the command prompt will look for programs to run? like in dos when you type copy, that's not really a dos command, that's actually a program that sits in your system32 folder.
well to add new paths to the global variable path you use the following command
path = (to change the path
%path% (to add the existing path that's already there)
; (to separate the directories)
c:\dos (and example of a path that you might add)
put it all together.
path = %path%;C:\dos
so in your case you might see this
c:\>PATH = C:\WINDOWS\system32;C:\WINDOWS
c:\>path = %path%;c:\dos
c:\>PATH = C:\WINDOWS\system32;C:\WINDOWS;c:\dos